MULTI PROCESSING

Multiprocessing

žMultiprocessing means multiple processors. Like an (octal– core and dual-core )

žMultiprocessing is an ability of a computer to use two or more processors for computer operations.

ž With multiple processors, the computer performance can be significantly increased.

Definition of multiprocessing

žIn multiprocessing OS more then one process can run on a different CPU at the same time so there is a real parallel execution of the process

Example of Multiprocessing

Symmetric multiprocessing

žAll CPU has the same function and access control

žOne OS control all CPUs and each CPU has equal rights. All are the same and not a slave and master

žThrough symmetric multiprocessing, one operating system can use all the CPUs at once (thus allowing several tasks to be performed simultaneously).

Asymmetric multiprocessing

žOne CPU will be master and others will be a slave. Master CPU will decide which the process will be handled by which CPU

Example of symmetric and Asymmetric

Advantages and disadvantages of multiprocessing

žHigh throughput (no: of jobs per unit time exp: m/s Nanosecond

žHigh reliability

žLow cost

žDisadvantages:

žLarge main memory

žComplex design

Multitasking

žIn the multitasking OS, each process is executed for a fixed time period. After that fixed time CPU switches to another process

žThis fixed time, the period is called Quantum.

žIt is also called a timeshare OS system.

žDuring multitasking, tasks such as listening to a CD or browsing the Internet can be performed in the background while using others in the foreground exp: word, song, Google, etc.

Example of multitasking

Multiprogramming

žMultiprogramming is also the ability of an operating system to execute more than one program on a single processor machine.

žMore than one task/program/job/process can reside in the main memory at one point in time. A computer running excel and Firefox browser simultaneously is an example of multiprogramming.

žMaximize CPU utilization.

žMore than one process in the main memory is ready to execute.

Example of Multiprogramming

MULTI PROCESSING

MULTI PROCESSING